import { Component, createRef } from "react";

// const dvRef = createRef();
class App extends Component {
    constructor() {
        super();
        this.dvRef = createRef();
    }
    componentDidMount() {
        console.log(this.dvRef.current);
    }
    render() {
        return <div ref={this.dvRef}>我是ref</div>;
    }
}
export default App;
